C-myc expression in the microvessels of medulloblastoma

The increased expression of c-myc is related to neoplastic transformation and angiogenesis. Therefore, the assessment of expression of c-myc in endothelial cells and neovascularization could help to determine the biological behavior of the tumor. We analyzed neovascularization and c-myc expression in 36 medulloblastoma specimens. The results were shown by determining immunohistochemical staining index (ISI), the sum of staining intensity (SI) and the percentage of positive cells (PPC) in the blood vessels endothelium of the tumor. We also performed the microvessel count (MVC) in 10 high-power fields (400X) with the most prominent vascularization and expressed it as microvessel density per mm2 (MVD). C-myc immunostaining intensity index in blood vessel endothelium is grouped into four groups, 0--no reaction, I-weak reaction (ISI = 1 or 2), II--moderate reaction (ISI = 3 or 4), III--strong reaction (ISI = 5 or 6). Statistically significant differences (p = 0.0214) have been found between groups 0 and 1 compared to groups 2 and 3. A higher percentage of positive cells has been found in male patients than in female ones (p = 0.0483). C-myc PPC 0 or 1 has on the average smaller density of blood vessels per mm2 than c-myc PPC 2 or 3, but the difference is not statistically significant. C-myc ISI 0 or 1 has, on the average, smaller density of blood vessels per mm2 than c-myc ISI 2 or 3, but the difference is not statistically significant. We concluded that c-myc staining intensity was associated with higher microvessels density.     

The chronology of third molar eruption in the Croatian population

Dental age estimation is common in orthodontics, paedodontics, paleodontology and forensic dentistry. The aim of this study was to assess chronological course of eruptive developmental phases of third molar and to establish parameters for the Croatian population. Sample of this study consisted of 1249 orthopantomograms of 530 (42.4%) male and 719 (57.6%) female subjects, aged 10 to 25 years. Eruptive phases were classified in 4 stages. No significant sex difference was found. Established chronology of the third molar eruption can be used as a standard for the assessment of dental age in clinical and forensic research on samples of Croatian population.     

Hydroxyapatite ceramics in multilevel cervical interbody fusion - is there a role?

The aim of this study is to evaluate the efficacy of hydroxyapatite grafts in multilevel cervical interbody fusion during the one year follow-up. A total of 86 patients with degenerative cervical disc disease underwent all together 224 cervical interbody fusion procedures in which either Smith-Robinson or Cloward type hydroxyapatite grafts were used. The surgeries included radiculopathy in 38 cases, myelopathy in 20 cases and myeloradicuopathy in 28 patients. In 65 out of 86 patients, fusion was followed by an anterior instrumentation (plating). Postoperatively, patients were followed for a mean of 15.64 (range 11-23.3) months. All patients underwent radiography to evaluate fusion and the axis curvature. Excellent clinical results (86%), described as a complete or partial relief of symptoms with full return to preop activity, were obtained in patients with radiculopathy. There were 5 grafts mobilizations and one graft fracture. Two grafts extruded in non-instrumented patients and required repeated surgery. There were other three reoperations due to the hardware problems. One year fusion rate was obtained at 86% for two-level surgery, 80.1% for three-level surgery and 74% for four-level surgery. The mean (SD) hospital stay was 3.8 (0.7) days. A hydroxyapatite cheramic can be a very effective synthetic material for multilevel cervical interbody fusion. It is characterized by a high fusion rate and a small percentage of graft-related complications, especially when fusion procedure is followed by plating.     

Advantages of intramedullar fixation in treatment of congenital tibial pseudoarthrosis--a case report

This report describes a case of a 29-year old patient with congenital pseudoarthrosis of the distal tibia previously treated unsuccessfully by a conventional surgical method. Tibial congenital pseudoarthrosis is a rare disease characterized by segmental osseous weakness resulting in deformation of the bone and spontaneous fractures which progresses to a tibial nonunion. In our case we used intramedullary stabilization with bone grafting and six month after operation congenital pseudarthrosis of the tibia healed.     

Osteolytic skull metastasis with dural involvement from a papillary thyroid carcinoma

Skull metastatic tumors are relatively rare medical entities and originate most often from the lungs, breast or prostate. We report a case of a 76-year-old woman who presented with a bulging, well-circumscribed mass on the right side of the forehead. Neuroimaging of the cranium detected an osteolytic lesion measuring 7 cm in the largest diameter while propagating outwards and intracranially. A thorough medical history revealed that patient had undergone surgery for invasive breast ductal carcinoma and also for a well-differentiated thyroid carcinoma 13 years ago. Considering patients medical history metastatic breast carcinoma was suspected. After a frontal craniotomy the tumour tissue was totally resected. Histological examination revealed metastatic papillary carcinoma characterized by ground-glass nuclei with intranuclear pseudo inclusion and nuclear grooves. We report clinical and neuroradiological features of this uncommon lesion and discussed the differential diagnosis of skull osteolytic lesion together with the treatment management.     

Visualization of CD44 and CD133 in Normal Pancreas and Pancreatic Ductal Adenocarcinomas: Non-overlapping Membrane Expression in Cell Populations Positive for Both Markers

Tumor-initiating cells of pancreatic ductal adenocarcinoma (PDAC) have been isolated based on expression of either CD133 or CD44. The authors aimed to visualize pancreatic cells simultaneously expressing both these cell surface markers by employing the same antibodies commonly used in cell-sorting studies. Normal and diseased pancreatic tissue, including 51 PDAC cases, were analyzed. CD44 and CD133 expression was determined by immunohistochemical double staining on formalin-fixed material and subcellular protein distribution evaluated by immunofluorescence/confocal microscopy. In the normal pancreas, CD44 and CD133 were coexpressed in the centroacinar regions but in non-overlapping subcellular compartments. As expected, CD44 was found mainly basolaterally, whereas CD133 was present on the apical/endoluminal membrane. This was also the case in chronically inflamed/atrophic pancreatic tissue and in PDAC. In some malignant ducts, CD44 was found at the apical cell membrane adjacent to but never overlapping with CD133 expression. CD44 level was significantly associated with the patient’s lymph node status. In conclusion, a CD44+/CD133+ cell population does exist in the normal and neoplastic pancreas. The preferentially centroacinar localization of the doubly positive cells in the normal parenchyma suggests that this population could be of particular interest in attempts to identify tumor-initiating cells in PDAC. This article contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.     

Effect of ambient extracellular glutamate on <Emphasis Type="Italic">Drosophila</Emphasis> glutamate receptor trafficking and function

Measurements suggest that the hemolymph glutamate concentrations in Drosophila are relatively high. This raises the possibility that extracellular glutamate could be an important regulator of glutamatergic transmission in vivo. Using voltage clamp electrophysiology, we found that synaptic currents in D. melanogaster larval neuromuscular junctions are reduced by extracellular glutamate (EC50: ~0.4 mM), such that only 10–30% of receptors were functionally available in 1 mM extracellular glutamate. The kinetics of synaptic currents were also slowed in a dose-dependent fashion (EC50: ~1 mM), consistent with the idea that extracellular glutamate preferentially removes the fastest-desensitizing receptors from the functional pool. Prolonged exposure (several hours) to extracellular glutamate also triggers loss of glutamate receptor immunoreactivity from neuromuscular junctions. To determine whether this receptor loss requires that glutamate bind directly to the lost receptors, we examined glutamate-dependent loss of receptor immunoreactivity in larvae with glutamate receptor ligand binding mutations. Our results suggest that glutamate-dependent receptor loss requires binding of glutamate directly to the lost receptors. To determine whether lost receptor protein is degraded or merely redistributed, we used immunoblots. Results suggest that glutamate receptor protein is redistributed, but not degraded, after prolonged exposure to high extracellular glutamate. K. Chen and H. Augustin contributed equally to this work.     

Invertebrate models of age-related muscle degeneration

Functional and structural deterioration of muscles is an inevitable consequence of ageing in a wide variety of animal species. What underlies these changes is a complex network of interactions between the muscle-intrinsic and muscle-extrinsic factors, making it very difficult to distinguish between the cause and the consequence. Many of the genes, structures, and processes implicated in mammalian skeletal muscle ageing are preserved in invertebrate species Drosophila melanogaster and Caenorhabditis elegans. The absence in these organisms of mechanisms that promote muscle regeneration, and substantially different hormonal environment, warrant caution when extrapolating experimental data from studies conducted in invertebrates to mammalian species. The simplicity and accessibility of these models, however, offer ample opportunities for studying age-related myopathologies as well as investigating drugs and therapies to alleviate them.     

Morphological features and isoenzyme characterization of endosymbiotic algae from green hydra

Symbiotic associations are of a wide significance in evolution and biodiversity. Green hydra is a typical example of endosymbiosis. In its gastrodermal myoepithelial cells, it harbors individuals of unicellular green algae. Morphological characteristics of isolated algae determined by light and electron microscopy are presented. Cytological morphometric parameters (cell area, cell radius, chloroplast area) of isolated algae from green hydra (Cx), as well as from reference species Chlorella kessleri (Ck) and Chlorella vulgaris (Cv), revealed similarity between the isolated endosymbiont and C. kessleri. Isoenzyme patterns of esterase (EST), peroxidase (POX), and catalase (CAT) were used for the investigation of genetic variability in endosymbiotic algae isolated from green hydra. Out of 14 EST isoenzymes observed in Cx species, 9 were expressed in the Cx sample. Results of the EST isoenzyme analysis indicated a higher degree of similarity between Cx and Cv than between Cx and Ck. Due to much higher heterogeneity, EST isoenzymes seem to be more suitable genetic markers for identification of different Chlorella species than CAT and POX isoenzymes. Results obtained suggest that symbiogenesis in green hydra has probably not been terminated yet.     

Presence of different phospholipase C isoforms in the nucleus and their activation during compensatory liver growth

Phospholipase C (PLC) was purified from the membrane-depleted rat liver nuclei. About 60% of the total PLC-activity corresponded to beta1b isoform, 30% to PLC-gamma1 and less than 10% to PLC-delta1. PLC-beta1b and -gamma1 were found in the nuclear matrix, while PLC-delta1 was detected in the chromatin. Two peaks of an increase in the total PLC-activity were detected occurring at 6 and 20 h after partial hepatectomy. An early increase in PLC-beta1b activity in the nuclear matrix was associated with serine phosphorylation of the enzyme, while the later increase paralleled the increase in the amount of protein. The increase in the PLC-gamma1 activity measured at 6 and 20 h after partial hepatectomy was associated with tyrosine phosphorylation of the enzyme. The activity of PLC-delta1 and the amount of the protein found in the chromatin was increased only at 20 h after partial hepatectomy.